To the extent that they actually do stuff, I believe they're liable to be prosecuted, but since they likely only deal with their husbands, perhaps there's often not enough actionable evidence to bring charges, unless the husband turns on his own wife(lol).

Of course if they DO have evidence, I don't think they'll hesitate to use that to leverage guilty pleas or cooperation on the husband, which I think is what they did with the Chin(his son, wasn't it?).